Fuel Pump problems, PLEASE HELP!!!!!!!!!!! Options

[tornik550]

I have been driving my car around for the past month without an alternator. Everything has been running great. Two nights ago, I installed a rebuilt bosch alternator and new voltage regulator. Everything ran great. I drove the car for about 5 minutes then it started to rain (I didn't have the relay board cover on and I do not have an engine rain tray). I put the car in the garage for the night. The next night, I took the car fro a drive. After about 10 minutes, I thought the electrical system died. The fuel pump was off but I did not notice if any other elctrical items were working. Thinking the alternator was the issue, I unhooked it, engine started and I drove home. I completely removed the alternator and went back to my old system of driving without an alternator.

Tonight (sans alternator), I tried to go on a date with my wife in my 914. I had the same issue- driving fine then fuel pump died. This time I noticed that all the other electrical stuff seemed to work fine. When I stopped, I turned the key, everything worked except fuel pump not working. I waited a few minutes and then the fuel pump started up- then died a few minutes later. I went through this several times- trying to limp the car home. Most importantly- wife was a good sport.

I went out side a few minutes ago, tried to start the engine- fuel pump not working. Hooked up a battery starter- fuel pump worked fine.

Ideas? Relay issue? I checked the fuses and their all ok.

[clarkcou]

Check the grounding point for the pump, rusted. Failing connection.

[76-914]

Could be fuel pump itself. Next time switch out the relay or jump it, check for voltage at fuel pump to verify. Brads site has a flow chart for fuel pump diagnostics. I've got all my bookmarks on IEx and can't get it for you, now. Maybe someone will post it for ya.

[mankowski]

Could be fuel pump itself. Next time switch out the relay or jump it, check for voltage at fuel pump to verify. Brads site has a flow chart for fuel pump diagnostics. I've got all my bookmarks on IEx and can't get it for you, now. Maybe someone will post it for ya.

This is the flow chart:
http://members.rennlist.com/pbanders/FPChecklist_frame.htm

[tornik550]

Short summary of what has been happening since my original problem- when I turn the key on, the pump starts and then slows to the point where it is no longer running. If you wait a few seconds then retry the fuel pump starts then dies a few seconds later.



Update-Now I am even more confused. My fuel pump was relocated under the fuel tank by the previous owner. Unfortunately, it is not accessible except by removing the tank (yes I plan on changing that). I took the tank out and checked the voltage at the at the pump. Reading was 11.72 volts. The reading at the battery was 12.20. I took the pump off and hooked it up directly to the battery and it ran fine. I have tried to swap out the relay for a known good relay and it didn't work.


One thing that I did find was that the line from the tank to the fuel pump was somewhat pinched. How do I test to see if my fuel pump is going bad? My pump is an inline carters- It is about 5 years old and only has about 500 miles on it (due to rebuild). During the years that the car was off the road, I assume the pump was filled with gas- if that matters.

PLEASE HELP!!!!

[ellisor3]

It could be that the pump is clogged with rust from the tank as well. It will run for a few seconds until the rust stopps it up again. Only solution is to pull the pump and clean it with brake cleaner or replace it.

[Dr Evil]

There is a voltage drop. Did you check the fuses on the circuit board in the engine bay? Remove it, clean the now corroded contacts that occurred after being doused in rain and left to dry, and put a shiny fuse in. Then see if you still get the voltage drop. You can measure the voltage drop across the current fuse if you like. If there is a change, then you have your answer. You need to find the missing voltage.

[Dave_Darling]

What fuel system do you have? L-jet, D-jet, carbs? I have a feeling that whomever relocated the pump didn't hook into the stock fuel-injection wiring to power the pump. So you should figure out where it draws power from.

If the pump is under the fuel tank, you may be able to access it from under the car. Remove the "gravel pan" that covers the steering rack; there is a ~6" hole from there into the tank compartment. You should be able to see the bottom of the tank and the fuel hoses through there. It's big enough to get a hand through, so see if you can get to the pump that way.

--DD

[Dr Evil]

He has carbs, so hopefully he can easily get this smaller pump out through the bottom hole. But, it sounds like he already pulled the tank.

[tornik550]

Unfortunately I was not able to get the pump out of the hole. I had to remove the tank.

I was able to spend more time with the pump today. I hooked it up directly to the battery just as I did last night. It worked fine however I left it hooked up for about 10 seconds and it slowed to a stop just like it does when it is installed in the car. So it appears that the pump is my problem.

I had an old facet style pump so I temporarily installed it until I can get a new pump. I installed it near the master cylinder so it will e easy to change out when I get a better pump. On to my next thread,